This invention relates to a guy hook used to attach guy wires to transmission line poles and more particularly to a guy hook used to attach down guys at a dead end transmission line pole.
The guy hook of the present invention is an improvement over prior art guy hook structures of the type disclosed, for example, in the U.S. Pat. No. 2,983,010 to O. W. Huggins, dated May 9, 1961. These prior art guy hooks generally include upper, central and lower body portions. The upper body portion includes a neck and ears for engaging the guy wire. The central body portion has frontward and rearward sides. The rearward side is in the shape of an inverted-U and provides a bearing surface between the hook and the pole. A channel is formed from this rearward inverted-U bearing surface to an aperture in the frontward side, the aperture and channel being adapted to receive a through-bolt therethrough to attach the hook to the pole. The lower body portion, or heel, of the hook includes spikes on a surface shaped to conform with circumference of the pole and which together with the aforenoted U-shaped bearing surface form the total contact region between the hook and the pole.
In the field, the installer will bore a hole in the dead end transmission line pole perpendicular to the vertical axis of the pole. The down guy hook is affixed to the pole by means of the through-bolt which is inserted through the aperture of the hook and through the bored hole and then tightened until the hook is firmly in contact with the pole and the spikes embedded therein. The down guy cable is engaged around the neck of the guy hook and tightened so that a downward and outward force is applied to the down guy hook. This force tends to cause the hook to move downward on the pole (down-slot) and to overturn and bend the through-bolt due to the moment created by the force. Resistance to the former is intended to be offered by the spiked heel. As noted in the aforenoted Huggins patent, the overturning action that tends to bend the through-bolt is intended to be eliminated by inclining the through-bolt channel so that its upper surface extends at an upward and outward angle from the rearward pole-engaging surface to permit the hook to be overturned by the downward and outward force without bending the through-bolt.
Performance of these prior art type of guy hooks in the field environment is frequently less than satisfactory. At the dead end of a transmission line, two of these prior art type of guy hooks are generally connected back-to-back on opposite side of the transmission line pole using a single through-bolt. A down guy cable is connected to one guy hook and a suspension strand cable (parallel to the ground) is connected to the opposite hook. In many of these installations, severe pole damage has been encountered. In particular, on the down guy side the overturning moment exerted on the hook has frequently bent the bolt, notwithstanding theoretical predictions otherwise. Furthermore, the heel has provided insufficient resistance and has been pulled downward and into the pole when the hook is overturned. On the span side, the rearward inverted-U central section of the hook has been found embedded into the pole. On both the down and span side, such damage threatens the structural integrity of the pole. Furthermore, overturning and downslotting of the down guy hook may loosen the tension on the down guy cable to a point that the pole is no longer firmly anchored.